The energetics, electronic properties, and magnetic moments of period 4 transition metals (TMs), intercalated within a h-BN twisted homobilayer were determine through first-principles calculations based on density functional theory within the local density approximation. These calculations were performed in periodic supercells containing a vacuum spacing of 10.4 Åand a bilayer twist angle of approximately \(9.43^\circ \)  corresponding to \((n,m)=(4,3)\)  and containing 74 B and 74 N atoms. Interactions between ion cores and valence electrons are described by the projector augmented-wave (PAW) method [1]}, [2]}, as implemented in the VASP package [3]}, [2]}. Plane waves with a kinetic energy cutoff of 400 eV were used as the basis set. As a lateral shift of the bilayers relative to each other can change the local chemical environment of a hexagonal site, care needed to be taken for structural relaxation of the TM intercalated bilyaer system. To investigate the energetics associated with the TM trapped at local minima in the moiré pattern, several bilayer atoms (most distant from the TM site) where constrained in the lateral direction in order to prevent relaxation of the system to the global energy minimum. Non-collinear spin was used for all calculations and constrained structural relaxation was performed until the maximum Hellman-Feynmann force on any atom in an unconstrained degree of freedom was below 0.01 eV/Å.
